Method and apparatus for loosening a jacket

ABSTRACT

A method for loosening a jacket includes the steps of pouring a molten metal into a mold having a jacket attached on its outer surface, while conveying the mold; cooling the mold after pouring while conveying the mold, after the step of pouring; and applying vibration to the jacket after the step of cooling.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. JP 2011-153825 filed on Jul. 12, 2011 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for loosening a jacket sticking to a mold, during production of a casting by a flaskless molding method in which casting is carried out with a flaskless mold.

2. Related Background Art

A flaskless molding method for production of a casting has been known in which casting is carried out with a flaskless mold (e.g. sand mold) (see Japanese Examined Utility Model Application Publication No. 56-14938 and Japanese Patent Application Laid-open No. 61-132266). This method comprises the steps of mounting and conveying a plurality of molds prior to pouring on a pouring line including a conveyor belt and pouring sequentially molten metal into the plurality of molds with a pouring apparatus; sequentially transferring the molds after pouring to a cooling line including a conveyor belt; and cooling the molds after pouring while conveying the molds on the cooling line.

Generally, a mold is formed with a combination of an upper mold and a lower mold. When molten metal is poured into molds by means of a pouring apparatus, the poured molten metal may sometimes uplift the upper mold. In order to prevent this uplifting of the upper mold, conventional methods employ a tapered jacket covering the outer circumference of the mold and a weight placed on the upper surface of the mold.

SUMMARY OF THE INVENTION

In order to remove a casting from the mold which has been subjected to pouring and cooling, the jacket and the weight are necessary to be detached from the mold. When, however, the jacket is attached to the mold for a long time after pouring, the jacket may stick to the mold and be difficult to be detached from the mold. In this case, it takes time to detach the jacket from the mold. Therefore, the jacket cannot be detached from the mold within a predetermined cycle time, resulting in undesired interruption of the line. Japanese Examined Utility Model Application Publication No. 56-14938 and Japanese Patent Application Laid-open No. 61-132266 do not disclose how to address to the problem when the jacket sticks to the sand mold; therefore, production efficiency may be affected when the conventional methods are employed.

There is a need in the art for a method and apparatus for loosening a jacket which facilitate the detachment of the jacket sticking to a mold and can improve production efficiency of castings.

A method for loosening a jacket according to an aspect of the present invention comprises the steps of: pouring a molten metal into a mold having a jacket attached on its outer surface, while conveying the mold; cooling the mold after pouring while conveying the mold, after the step of pouring; and applying vibration to the jacket after the step of cooling.

In the method according to the aspect of the present invention, vibration is applied to the jacket after the step of cooling, thereby loosening the jacket sticking to the mold. Accordingly, in a step of detaching the jacket from the mold after the step of applying vibration, the jacket can be detached from the mold without hindrance. As a result, the jacket can be detached from the mold within a predetermined cycle time, allowing an improvement in production efficiency of a casting.

In the step of applying vibration, vibration may be applied to the jacket in a vertical direction relative to the jacket. This allows easier detachment of the jacket from the mold.

In the step of applying vibration, vibration may be applied to the jacket in the vertical direction relative to the jacket by ascending and descending a supporting part that supports the jacket by a cylinder connected to the supporting part. This allows easier detachment of the jacket from the mold.

In the step of applying vibration, a controller may repeatedly send descending and ascending signals to the cylinder when, after sending an ascending signal to the cylinder, the controller does not receive a detection signal within a predetermined time from a sensor that detects an arrival of the supporting part at a top position by means of the cylinder. In this case, vibration is applied to the jacket sticking to the mold, but not to the jacket which is not sticking to the mold. As a result, production efficiency of a casting can further be improved.

The method may further comprise, after the step of applying vibration, the step of removing the mold from a position where vibration has been applied to the jacket and, after the step of removing, the step of detaching the jacket from the mold.

An apparatus for loosening a jacket according to another aspect of the present invention comprises a vibrator which is positioned upstream of a detaching apparatus that detaches a jacket from a mold having the jacket attached to its outer surface and having been subjected sequentially to pouring and cooling, and which applies vibration to the jacket before the jacket is detached from the mold by means of the detaching apparatus.

The apparatus according to another aspect of the present invention comprises a vibrator which applies vibration to a jacket sticking to a mold having been subjected to pouring and cooling, thereby loosening the jacket sticking to the mold. Accordingly, in the detaching apparatus, the jacket can be detached from the mold without hindrance. As a result, the jacket can be detached from the mold within a predetermined cycle time, allowing improvement in production efficiency of a casting.

The vibrator may include a supporting part that supports the jacket, and a cylinder that ascends and descends the supporting part. A controller which sends, to the cylinder, a signal for vertically reciprocating the cylinder may be further provided. This allows easier detachment of the jacket from the mold.

The apparatus may further comprise a sensor that detects an arrival of the supporting part at a top position by means of the cylinder, and the controller may repeatedly send descending and ascending signals to the cylinder when, after sending an ascending signal to the cylinder, the controller does not receive a detection signal from a sensor within a predetermined time. In this case, vibration is applied to the jacket sticking to the mold, but not to the jacket which is not sticking to the mold. As a result, production efficiency of a casting can further be improved.

According to various aspects of the present invention, the jacket sticking to the mold can be easily detached from the mold and production efficiency of a casting can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view illustrating a casting production system;

FIG. 2 is an arrow view taken along line A-A of FIG. 1 illustrating a cooling line;

FIG. 3 is an arrow view taken along line B-B of FIG. 1 illustrating a pouring line;

FIG. 4 is an arrow view taken along line C-C of FIG. 1 illustrating a jacket loosening apparatus;

FIG. 5 is an arrow view taken along line D-D of FIG. 1 illustrating a jacket transferring apparatus;

(A) of FIG. 6 is a front view of the jacket loosening apparatus with the supporting part at its bottom position, and (B) of FIG. 6 is a side view of the jacket loosening apparatus with the supporting part at its bottom position;

(A) of FIG. 7 is a front view of the jacket loosening apparatus with the supporting part at its top position, and (B) of FIG. 7 is a side view of the jacket loosening apparatus with the supporting part at its top position; and

(A) of FIG. 8 is a front view of the jacket loosening apparatus with the supporting part at its bottom position, and (B) of FIG. 8 is a side view of the jacket loosening apparatus with the supporting part at its bottom position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention are now illustrated with reference to the drawings. The same symbol represents the same element, and duplicated explanations are omitted.

First of all, the configuration of a casting production system 100 is illustrated. As shown in FIG. 1, the casting production system 100 comprises a flaskless molding machine 7, a pouring line 2, a cooling line 3, transferring apparatuses 4A, 4B, and 9 and a mold discharging apparatus 23.

The flaskless molding machine 7 is placed at the upstream end (at the side of the transferring apparatus 4B in the present embodiment) of the pouring line 2. The flaskless molding machine 7 produces flaskless molds (sand molds) 5 from sand at a regular takt time. The mold 5 is, as shown in FIGS. 4 to 7, formed of a combination of an upper mold 5 a and a lower mold 5 b. The outer circumference surface of the mold 5 has a tapered shape in which the length of the outer circumference decreases toward the top of the mold.

The pouring line 2 includes, as shown in FIGS. 1 and 3, a linear conveyor belt. A plurality of surface plate trucks 6 is mounted on the pouring line 2. The pouring line 2 feeds from the upstream side (the side of the transferring apparatus 4B according to the present embodiment) to the downstream side (the side of the transferring apparatus 4A according to the present embodiment) each surface plate truck 6 at fixed pitches with a regular takt time. Each mold 5 produced in the flaskless molding machine 7 is mounted on each surface plate truck 6. A pouring area 12 is provided lateral to the pouring line 2 and between the transferring apparatus 9 and the transferring apparatus 4A, where molten metal is poured into the molds 5.

The cooling line 3 includes, as shown in FIGS. 1 and 2, a linear conveyor belt. The cooling line 3 is provided to be parallel to the pouring line 2. A plurality of surface plate trucks 6 is mounted on the cooling line 3. The cooling line 3 feeds from the upstream side (the side of the transferring apparatus 4A according to the present embodiment) to the downstream side (the side of the transferring apparatus 4B according to the present embodiment) each surface plate truck 6 at fixed pitches with a regular takt time.

The transferring apparatuses 4A and 4B are, as shown in FIGS. 1 to 3, provided at each end of the pouring line 2 and cooling line 3, respectively. The transferring apparatuses 4A and 4B have a supporting part (not shown) which supports the surface plate truck 6, a lifting part (not shown) which ascends and descends the supporting part, and a conveyance part (not shown) which conveys the supporting part between the pouring line 2 and the cooling line 3.

The transferring apparatus 4A transfers the surface plate trucks 6 from the pouring line 2 to the cooling line 3. The transferring apparatus 4B transfers the surface plate trucks 6 from the cooling line 3 to the pouring line 2. Accordingly, the surface plate trucks 6 circulate between the pouring line 2 and the cooling line 3.

The transferring apparatus 9 is, as shown in FIGS. 1 to 3, provided at the side of the transferring apparatus 4B relative to the center of the pouring line 2 and cooling line 3 in the longitudinal direction. The transferring apparatus 9 has, as shown in FIGS. 1 to 3 and 5, a gate-shaped frame 9 a provided astride the pouring line 2 and the cooling line 3, a jacket transferring part 9 b attached to the frame 9 a, a weight transferring part 9 c attached to the frame 9 a and a loosening apparatus 18 which loosen a jacket 11.

The jacket transferring part 9 b conveys the jacket 11 from the cooling line 3 to the pouring line 2, wherein the jacket 11 is a cylinder having diameters decreasing from one end to the other. The shape of the inner circumference surface of the jacket 11 corresponds to the shape of the outer circumference surface of the mold 5. On the end of the jacket 11 having the smaller diameter, a flange part 25 is provided which protrudes outwardly.

The jacket transferring part 9 b has, as shown in FIG. 5, a supporting part 9 b ₁ which supports the flange part 25 of the jacket 11, a lifting part 9 b ₂ which ascends and descends the supporting part 9 b ₁, and a conveyance part 9 b ₃ which conveys the supporting part 9 b ₁ between the pouring line 2 and the cooling line 3 (between a detaching position 16 of the jacket 11 and an attaching position 17 of the jacket 11). The jacket transferring part 9 b supports the jacket 11 attached to the outer circumference surface of the mold 5 which is transferred on the cooling line 3 by means of the supporting part 9 b ₁ and lifts the jacket 11 with the lifting part 9 b ₂.

Under this situation, the jacket transferring part 9 b transfers the jacket 11 by means of the conveyance part 9 b ₃ onto the pouring line 2 (to the attaching position 17 of the jacket 11), and descends the jacket 11 by means of the lifting part 9 b ₂. Accordingly, the jacket transferring part 9 b attaches the jacket 11 onto the outer circumference surface of the mold 5 which is being conveyed on the pouring line 2. The jacket 11, which is attached onto the outer circumference surface of the mold 5, prevents the upper mold 5 a being uplifted by poured molten metal.

The weight transferring part 9 c conveys the weight 10 from the cooling line 3 to the pouring line 2. The weight transferring part 9 c has a supporting part (not shown) which supports the weight 10, a lifting part (not shown) which ascends and descends the supporting part, and a conveyance part (not shown) which conveys the supporting part between the pouring line 2 and cooling line 3 (between a detaching position 13 of the weight 10 and a mounting position 14 of the weight 10). The weight transferring part 9 c supports the weight 10 mounted on the upper surface of the mold 5 which is being conveyed on the cooling line 3 by means of the supporting part and lifts the weight 10 by means of the lifting part.

Under this situation, the weight transferring part 9 c transfers the weight 10 by means of the conveyance part onto the pouring line 2 (to the mounting position 14 of the weight 10) and descends the weight 10 by means of the lifting part. Accordingly, the weight transferring part 9 c mounts the weight 10 on the upper surface of the mold 5 which is being conveyed on the pouring line 2. The weight 10, which is placed on the upper surface of the mold 5, prevents the upper mold 5 a being uplifted by poured molten metal.

As shown in FIGS. 1, 2 and 4, the loosening apparatus 18 for loosening the jacket 11 sticking to the mold 5 is attached to the frame 9 a so that it is positioned above the cooling line 3 and at further upstream of the cooling line 3 to the transferring apparatus 9. The loosening apparatus 18 has, as shown in FIGS. 4 and 6, a gate-shaped arm 24 having a nail part 20 protruding inwardly, a cylinder 19 which ascends and descends the arm 24, a guiding part 27, an upper sensor 21, a lower sensor 22 and a controller 30.

The arm 24 supports the jacket 11 with its nail part 20 coming into contact with the flange part 25 of the jacket 11. The cylinder 19 has a main body 19 a and an extendable rod 19 b. The main body 19 a is attached to the frame 9 a. The extendable rod 19 b is connected to the arm 24. An input control signal from the controller 30 causes extension and contraction of the extendable rod 19 b in the vertical direction, so that the cylinder 19 ascends and descends the arm 24.

The guiding part 27 has a main body 27 a and a guiding rod 27 b. The main body 27 a has a cylindrical shape along the vertical direction and is attached to the frame 9 a. The guiding rod 27 b is inserted into the main body 27 a so as to be able to slide into the main body 27 a. A protrusion 28 is provided at the upper end of the guiding rod 27 b, which is detectable by the upper sensor 21 and the lower sensor 22. The lower end of the guiding rod 27 b is attached to the arm 24. When the arm 24 is ascended and descended by the cylinder 19, the guiding rod 27 b moves in the vertical direction guided by the main body 27 a.

The upper sensor 21 and the lower sensor 22 are attached to a pole 26 which is installed in a protruding manner on the upper surface of the frame 9 a. The upper sensor 21 is located on the side surface of the pole 26 (see FIG. 7) so that it faces the protrusion 28 at the upper end of the guiding rod 27 b when the arm 24 moves from, by means of the cylinder 19, its original position (see FIG. 8) to top position. The upper sensor 21 sends a signal to the controller 30 that indicates an arrival of the arm 24 at the top position when the protrusion 28 is positioned laterally to the upper sensor 21.

The lower sensor 22 is located on the side surface of the pole 26 (see FIG. 6) so that it faces the protrusion 28 at the upper end of the guiding rod 27 b when the arm 24 moves, by means of the cylinder 19, to the bottom position. The lower sensor 22 sends a signal to the controller 30 that indicates an arrival of the arm 24 at the bottom position when the protrusion 28 is positioned laterally to the lower sensor 22.

The controller 30 controls ascending and descending of the cylinder 19 based on signals from the upper sensor 21 and the lower sensor 22, and applies vibration to the jacket 11 through the arm 24. More specifically, the controller 30 repeatedly sends descending and ascending signals to the cylinder 19, when, after sending an ascending signal to the cylinder 19, a detection signal from the upper sensor 21 is not received within a predetermined time.

The mold discharging apparatus 23 is, as shown in FIG. 1, located at the downstream end (on the side of the transferring apparatus 4B according to the present embodiment) of the cooling line 3. The mold discharging apparatus 23 discharges the mold 5 which is detached from the jacket 11 and weight 10 in the transferring apparatus 9. In this downstream step, a casting is removed from the mold 5.

An action of the casting production system 100 is now illustrated with a focus on the mold 5. The mold 5 produced in the flaskless molding machine 7 is mounted on the surface plate truck 6 in the pouring line 2. The mold 5 mounted on the surface plate truck 6 moves towards the downstream side on the pouring line 2. When the mold 5 then arrives at the transferring apparatus 9, the jacket 11 is attached to the outer circumference surface of the mold 5 by means of the jacket transferring part 9 b as well as the weight 10 is mounted on the upper surface of the mold 5 by means of the weight transferring part 9 c.

The mold 5 which is attached with the jacket 11 and the weight 10 in the transferring apparatus 9 then moves towards the downstream side on the pouring line 2. When the mold 5 arrives at the pouring area 12, molten metal is poured into the mold 5. Due to high temperature of molten metal, vapor is generated in pouring and penetrates into the mold (sand mold) 5.

When the mold 5 then arrives at the transferring apparatus 4A, it is transferred from the pouring line 2 to the cooling line 3 together with the surface plate truck 6 by means of the transferring apparatus 4A. The mold 5 is cooled down while it moves towards the downstream side on the cooling line 3. During this cooling, vapor penetrated into the mold 5 during pouring is cooled down, so that water is generated between the mold 5 and the jacket 11, thereby making the jacket 11 being easily stuck to the mold 5.

When the mold 5 arrives at the transferring apparatus 9, the controller 30 sends an ascending signal to the cylinder 19 so as to ascend the arm 24. When the jacket 11 does not stick or slightly sticks to the mold 5, the jacket 11 can be easily detached from the mold 5, so that the arm 24 lifting the jacket 11 arrives at the top position within a predetermined time. At this time, the upper sensor 21 detects the presence of the protrusion 28 laterally to the upper sensor 21 and sends a signal to the controller 30 indicating an arrival of the arm 24 at the top position.

When, on the other hand, the jacket 11 sticks to the mold 5 and cannot be easily detached from the mold 5, the arm 24 does not arrive at the top position within a predetermined time. When a detection signal from the upper sensor 21 is not received within a predetermined time, the controller 30 descends the arm 24 to the bottom position once before repeatedly sending descending and ascending signals to the cylinder 19, thereby applying vibration to the jacket 11. The jacket may be repeatedly vibrated until the upper sensor 21 detects the protrusion 28. Output of the cylinder 19 may be such that it can lift the weight of the jacket 11 but cannot lift the weight of the jacket 11 with the mold 5. This makes the mold 5 to be less uplifted from the surface plate truck 6 when vibration is applied to the jacket 11. Therefore, damage to the mold 5 by repeated collisions of the mold 5 with the surface plate truck 6 can be prevented.

In the weight transferring part 9 c, the weight 10 is then removed from the upper surface of the mold 5. The removed weight 10 is transferred, by means of the weight transferring part 9 c, to a mold 5 on the pouring line 2 next to the mold 5 from which the weight 10 has removed. In the jacket transferring part 9 b, the jacket 11 is then removed from the outer circumference surface of the mold 5. The removed jacket 11 is transferred, by means of the jacket transferring part 9 b, to a mold 5 on the pouring line 2 next to the mold 5 from which the jacket 11 has removed.

The mold 5 then moves towards the downstream side on the cooling line 3. When the mold 5 arrives at the mold discharging apparatus 23, it is transferred from the surface plate truck 6 to the mold discharging apparatus 23 and discharged to the downstream step. In this downstream step, a casting is removed from the mold 5, thereby completing the production of the casting. When, on the other hand, the surface plate trucks 6 from which the mold 5 has removed arrives at the transferring apparatus 4B, it is transferred from the cooling line 3 to the pouring line 2 by means of the transferring apparatus 4B and the above steps are repeated.

In the above-described present embodiment, the jacket 11 sticking to the mold 5 after pouring and cooling is loosened from the mold by applying vibration to the jacket 11. Therefore, even when the jacket 11 sticks to the mold 5, the jacket 11 is ensured to be loosened from the mold 5 by vibration. Accordingly, the jacket 11 can be detached from the mold 5 without hindrance in the jacket transferring part 9 b. As a result, the jacket 11 can be detached from the mold 5 within a predetermined cycle time, preventing troubles such as the line interruption and improving production efficiency of castings.

According to the present embodiment, the controller 30 controls the cylinder 19 so as to vibrate the arm 24 in the vertical direction when the controller 30 does not receive a detection signal from the upper sensor 21 within a predetermined time. Thus, vibration is applied to the jacket 11 sticking to the mold 5 but is not applied to the jacket 11 which is not sticking to the mold 5. Therefore, production efficiency of castings can be improved.

The embodiment of the present invention is described in detail as above. However, the present invention is not limited to the above embodiment. For example, vibration is applied to the jacket 11 in the vertical direction according to the present embodiment; however, vibration may be applied in a horizontal direction or oblique directions.

According to the present embodiment, the jacket 11 to be vibrated is selected based on a detection signal from the upper sensor 21; however, vibration may be applied to all jackets 11 without such selection.

The means for applying vibration to the jacket 11 is not limited to the cylinder 19 illustrated in the present embodiment and any various known vibration application means can be employed such as a vibration motor.

The original position for the loosening apparatus 18 according to the present embodiment is, as shown in FIG. 8, the position where the arm 24 is at the bottom position. In this situation, the mold 5 arrives at the transferring apparatus 9. The loosening apparatus 18 can also be used as an apparatus which ascends and descends the jacket 11 and the weight 10. 

1. A method for loosening a jacket, comprising the steps of: pouring a molten metal into a mold having a jacket attached on its outer surface, while conveying the mold; cooling the mold after pouring while conveying the mold, after the step of pouring; and applying vibration to the jacket after the step of cooling.
 2. The method according to claim 1, wherein, in the step of applying vibration, vibration is applied to the jacket in a vertical direction relative to the jacket.
 3. The method according to claim 2, wherein, in the step of applying vibration, vibration is applied to the jacket in the vertical direction relative to the jacket by ascending and descending a supporting part that supports the jacket by a cylinder connected to the supporting part.
 4. The method according to claim 3, wherein, in the step of applying vibration, a controller repeatedly sends descending and ascending signals to the cylinder when, after sending an ascending signal to the cylinder, the controller does not receive a detection signal within a predetermined time from a sensor that detects an arrival of the supporting part at a top position by means of the cylinder.
 5. The method according to claim 1, further comprising the steps of: removing the mold from a position where vibration has been applied to the jacket, after the step of applying vibration; and detaching the jacket from the mold after the step of removing.
 6. An apparatus for loosening a jacket, comprising: a vibrator which is positioned upstream of a detaching apparatus that detaches a jacket from a mold having the jacket attached to its outer surface and having been subjected sequentially to pouring and cooling, and which applies vibration to the jacket before the jacket is detached from the mold by means of the detaching apparatus.
 7. The apparatus according to claim 6, wherein the vibrator includes a supporting part that supports the jacket, and a cylinder that ascends and descends the supporting part, and a controller which sends, to the cylinder, a signal for vertically reciprocating the cylinder is further provided.
 8. The apparatus according to claim 7, further comprising a sensor that detects an arrival of the supporting part at a top position by means of the cylinder, wherein the controller repeatedly sends descending and ascending signals to the cylinder when, after sending an ascending signal to the cylinder, the controller does not receive a detection signal from the sensor within a predetermined time. 